BBC World News | 30th October 2017 Onwards

That surprises me re cameras, I would have thought it would be switchable/patchable so that "camera 4" could be fed from any wallbox rather then hard wired.

For example so that when the One Show wheel a camera or two outside and plug them into the exterior wallbox they appear as the same source at the mixer.

The wall box or term panel connection (when it comes to Studio or OB cameras, that will be 'rackable') is
the Triax connection, that will lead to that camera's CCU or 'base unit', and that sits in the equipment room (that can be 10s or even a 100 metres away from the studio floor). The SDI video output of the camera is taken from the CCU, there are typically two or three SDI outputs available. As Noggin says, one of those will often be directly wired to the mixer crate (again this will often be some distance from the gallery, but typically in bays local to the CCUs (and other studio electronics). One of the other CCU outputs will feed the studio router too.

It's only in non rackable situations, (College Green, HoC lobby etc) where you'd take a direct video output from the camera, straight to a wall box. Multiple camera set ups have to be in a 'rackable' set up, because you have to colour match etc all of them (called racking, (or in Europe, shading) )

That is indeed the case - and hardwiring a camera channel to a vision mixer doesn't cause any change to that.

This is because camera cable patching happens upstream of the CCU - the Camera Control Unit (aka the Base Station) - of the camera, and the connection of the CCU to the mixer is thus downstream of any camera cable patching.

Studio and OB cameras aren't wired directly to vision mixers by the cable plugged into the back of the camera. Broadcast cameras used on studios and OBs in general don't use HD-SDI outputs. The triax or fibre camera cable from the back of the camera is patched to a CCU, and the output of that CCU is then fed to the vision mixer and/or router. The CCU remains fixed and can be hardwired to the vision mixer - CCU 1's output is 'Camera 1' however the camera is cabled to it. The triax or fibre cable routes feeding the camera head to the CCU can be varied and manually replugged as required.

You can have lots of different cable routes to connect a camera head to a CCU - via wallboxes, multiple cable drops etc. but camera 1's output will be from camera 1's CCU, and it is the CCU output that is hardwired to the vision mixer.



Yes - that happens because Camera 1 is still connected to the same CCU, just by different cable routes. The CCU for camera 1 can still be hardwired to the same vision mixer input in this scenario.

When a camera moves from one wallbox, or cable drop, to another in a studio or on an OB all that needs to happen is that the camera is connected to a new cable or route at the camera head, and the other end of that cable or route is plugged into the same CCU at the other end (either on the OB truck tailboard or on a triax/fibre patch panel feeding CCUs).

This patch panel will allow you to chose which wallbox connection is connected to which camera's CCU at any given time, as this camera patching happens upstream of the CCUs - it is also upstream of any router or hard wiring and has no impact on whether a CCU output is fed to the mixer via a router or directly, bypassing the router.

Camera 1's CCU output is Camera 1 on the mixer however the fibre or triax patching between the camera head and Camera 1 CCU happens.

Since you mention patching is it possible for a CCU to handle another camera of the same make or family or are they a married pair?

They are not a married pair, they just need to be compatible models

No you can mate any compatible camera head with a compatible CCU from the same manufacturer. Manufacturers often allow older CCUs to talk to newer camera heads to reduce upgrade costs or aid flexibility in deployment across a fleet ISTR.

The CCU will talk to whichever compatible camera head is at the other end of its cable. (If they were a married pair it would be a nightmare on OBs or shows where camera heads and CCUs are shared between studios, and you need to be able to quickly swap out a faulty camera head without having to also swap out a CCU)

On some shows it's entirely conceivable to re-patch a DIFFERENT camera head to the same CCU during a show - rather than having to repo the camera head (though you may repo the operator) - giving you effectively two different camera 1s or two different camera 4s during a show... This is particularly useful if you have cameras on mountings that are difficult to repo or de-rig and re-rig quickly and can mean a reduction in costs (you don't need 2 full chains of CCU/RCP/HEAD, just 1 chain and an extra head) or allow you to run more cameras into a facility wired for fewer cameras.

No children then?

Any reason why when going into and out of an ad break there is always a judder/jump in picture? Happens every time.

Could it be a new form of hippy shakes?

Yup. I've wondered that too.

I see that there's no B100D or WNT on BBC Four this week, does that mean World News is now in the gallery for C 24/7?

Yes. Although Focus on Africa usually decamps from B to C one week later on. If I recall correctly, Focus stayed in B for an extra week last year and also continued throughout the "holiday" season, whereas all other branded strands were replaced by generic World News from C at progressive stages before Christmas.

It's also a rare chance to see Ros Atkins seated and wearing a tie for a change, whilst his Milk Tray Man outfit goes for annual laundering.